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The Consumer Technology Association(CTA) and LonMark International have announced that the ANSI/CTA-709.7 LON IP is now approved as a new American National Standard (ANS) by the American National Standards Institute (ANSI). The new standard focuses on the interoperability of Internet of Things (IoT) devices and provides a complete model for implementing LON IP device-to-device and device-to-application communication interoperability.This new standard will provide multiple parties – including users, developers, vendors, integrators and specifiers of open building control systems – a mechanism to develop and deliver a higher level of interoperability using native Ethernet/IP based devices. The new standard describes the complete set of requirements for vendors to develop LON devices with native IP communications, which offers higher speed and better IT integration flexibility. As more building control networks require more data and more IoT application interfaces, this new media type for LON control networks provides all of the benefits and functionality to meet this growing demand.

The ANSI/CTA-709.7 Implementation Guidelines define the application layer requirements for interoperable devices to communicate directly on Ethernet. It defines the addressing requirements for both IPv4 and IPv6. LonMark will offer full interoperability testing of any device utilizing the new channel type. The standard defines all of the timing parameters, configuration, and interface requirements to the full 709.1 protocol stack.

A few years prior the ANSI/CTA-709.6 Application Elements built upon the ANSI/CTA-709.5 Implementation Guidelines by providing a catalog of more than 100 common device profiles, with more than 380 specific implementation options. These profiles define the mandatory and optional design requirements for standard data variables, standard configuration properties, enumeration types and standard interface file requirements. This extensive library of device profiles includes definitions for a broad collection of devices for HVAC, indoor and outdoor (roadway) lighting, security, access, metering, energy management, fire and smoke control, gateways, commercial and industrial I/O, gas detection, generators, room automation, renewable energy, utility, automated food service, semiconductor fabrication, transportation, home appliances and others.

RECOM has expanded its low power AC/DC portfolio with encapsulated 5 W power supplies, which operate up to +90°C. They accept input voltage lines of up to 305 VAC and offer peak power capability up to 6 W. These modules are well suited for Industry 4.0, IoT and smart household applications requiring features that go beyond the industry standard.

With its RAC05-K/277 series, RECOM introduces 5 W AC/DC converters that support peak power needs and are specially designed for extended input lines and reliable operation at extreme temperatures from -40°C up +90°C. The RAC05-K/277 series are built to operate from extended input lines with mains voltages from 85 VAC up to 305 VAC, are EMC compliant to EN55022 class “B” with a minimum 6 dB margin on both radiated and conducted readings without the need for external components.

At a 1” x 1.25” footprint, these new PCB-mount or wired modules feature fully protected outputs and international safety certifications for industrial, household and ITE for worldwide use. The RAC05-K/277 series is an addition to RECOM’s ultra-compact RAC05-K converters with a 1” x 1” footprint, as well as the recently released RAC05-K/480, an AC/DC module dedicated for phase-to-phase operation up to 528VAC and exclusive only to RECOM. Wired versions of the RAC05-K/277 series are due to be released in October of 2018. Samples of the pin-versions and OEM pricing are available from all authorized distributors or directly from RECOM.

Your choice of power supply can have a major impact on your embedded system’s capabilities. Power supply innovators are smoothing the way with devices designed to match application needs.

By Jeff Child, Editor-in-Chief

Arguably the unsung heroes of any embedded system design, power supplies and converters are critical enablers for meeting today’s needs. As embedded systems pack ever more intelligence into smaller spaces, power has direct implications on the size, cooling and mobility of any system.

To keep pace, power supply vendors continue to roll out more efficient products, new partitioning strategies and more compact solutions. In tandem to those trends, there’s a growing demand to reduce size, weight and power of system electronics. Driving those demands is a desire to fit more functionality in the same space or into a smaller footprint.

If you look at the power supply products released over the last 12 months, there’s been a definite uptick in new products that have some sort of application or industry focus. While this hasn’t diminished the role of general purpose power supplies, the trend has been toward supplies that include either certifications, special performance specs or tailored packaging intended for a specific application area such as medical, industrial, railway or the IoT.

Power Supplies for Medical

An example along those lines in the medical space is the TDK-Lambda brand CUS150M series of AC-DC 150 W rated power supplies announced early this year by TDK (Figure 1). The device has the capability of operating in ambient temperatures of up to 85°C without the need for forced air cooling. Certified to medical and ITE standards for Class I and II (no earth ground connection) operation, the product meets both curve B radiated and conducted emissions. CUS150M target applications include medical, home healthcare, dental, test and measurement, broadcast and industrial equipment.

Figure 1The CUS150M series of AC-DC 150 W rated power supplies are certified to medical and ITE standards for Class I and II operation. It meets both curve B radiated and conducted emissions.

Output voltage options include 12 V, 15 V, 18 V, 24 V, 28 V and 36 V models. The CUS150M operates from an 85 VAC to 264 VAC input and has operating efficiencies up to 91%. Off-load power consumption is less than 0.5 W and a 10 V to 12 V, 0.5 A fan supply is fitted as standard.

The open frame version is in the industry standard 50.8 mm x 101.6 mm (2″ x 4″) footprint with a height of 31.5 mm. Convection cooled it can deliver 120 W at 40°C, or with forced air cooling 150 W at 50°C, 140 W at 70°C and 75 W at 85°C. With the U-channel construction variant, measuring 64 mm x 116 mm x 38.5 mm, the CUS150M can be conduction cooled via a cold plate to deliver 150 W at 50°C, 100 W at 70°C and
50 W at 80°C. Cover or top fan options are also available.

Input to output isolation is 4 kVAC (2xMoPP (Means of Patient Protection)), input to ground 1.5 kVAC (1xMoPP) and output to ground 1.5 kVAC (1xMoPP) making the series suitable for B and BF rated medical equipment. Touch current is a maximum of 100 µA, with leakage current less than 250 µA. 5,000 m is the maximum operating, transportation and storage altitude.

Encapsulated Converters

Also targeting medical applications, Minmax Technology offers its Minmax MAU01M / MSCU01M series, a range of high performance 1 W medical safety approved DC-DC converters with encapsulated SIP-7 and SMD packages. They are specifically designed for medical applications. The series includes models available for input voltages of 4.5 VDC to 5.5 VDC, 10.8 VDC to 13.2 VDC, and 21.6 to
26.4 VDC. The I/O isolation is specified for 4,000 VAC with reinforced insulation and rated for a 300 VRMS working voltage.

Additional features include short circuit protection, a low leakage current of 2 μA max. and operating ambient temperature range of -40°C to 95°C. This is achieved without de-rating and with a high efficiency of up to 84%. The MAU01M / MSCU01M series conforms to the 4th edition medical EMC standard. It meets 2xMoPP per 3rd edition of IEC/EN 60601-1 and ANSI/AAMI ES60601-1. The MAU01M / MSCU01M series offers an economical solution for demanding medical instrument applications that require a certified supplementary and reinforced insulation system to comply with latest medical
safety approvals under the 2xMoPP requirements.

Meanwhile, CUI’s Power Group added five open frame series products, ranging from
180 W up to 550 W, to its line of internal AC-DC medical power supplies (Figure 2). Certified to the medical 60601-1 edition 3.1 safety standards for 2xMoPP applications and 4th edition EMC requirements, the VMS-180, VMS-225, VMS-275, VMS-350 and VMS-550 series feature high efficiency up to 94% and high-power densities up to 30 W/in3. The devices are housed in 2″ x 4″ (50 mm x 101 mm) and 3″ x 5″ (76 mm x 127 mm) packages with profiles measuring as low as 0.75″ (19 mm), providing a compact, high density solution fokproviding a compact, high density solution for medical diagnostic equipment, medical monitoring devices and dental applications.

All of these VMS series supplies provide output voltage options from 12 VDC to 58 VDC, feature wide universal input voltage ranges from 80 VAC to 264 VAC and offer no-load power consumption as low as 0.5 W. The 180 W to 550 W models also carry an input to output isolation of 4,200 VAC with leakage current ratings as low as 0.3 mA at 230 VAC. Operating temperatures range at full load from -40°C up to +50°C with forced air cooling, derating to 50% load at +70°C.

Other features include protections for over voltage, over current and short circuit, along with power factor correction and a 12 VDC / 500 mA fan output. These medical power supplies further meet EN 55011 Class B limits for conducted and radiated emissions and achieve an MTBF of 3.37 million hours, calculated per Telcordia SR-332 Issue 3. …

Note: We’ve made the October 2017 issue of Circuit Cellar available as a free sample issue. In it, you’ll find a rich variety of the kinds of articles and information that exemplify a typical issue of the current magazine.

Telit has announced that Verizon has certified several of its LTE products. The seven modules are part of Telit’s portfolio of LTE Cat M1, Cat 1, Cat 4 and Cat 11 products, with the LE910-SV V2 and LE910B1-NA modules that also supports Verizon’s Voice over LTE (VoLTE) technology. The modules are now available for operation on Verizon’s 4G LTE network. The following modules are included: ME910C1-NV LTE Cat M1 module, LE910-NA V2 LTE Cat 4 module, LE910-SV V2 LTE Cat 4 VoLTE module, LE910B1-NA LTE Cat 1 VoLTE module, ME866A1-NV LTE Cat M1 module, LE866-SV1 LTE Cat 1 module and LM940 LTE Cat 11 mini PCIe module.The ME910C1-NV, LE910-SV V2 and LE910-NA V2 modules are members of Telit’s xE910 family (shown). And the LE866-SV1, one its xE866 family, is one of the smallest cellular modules in the market. Any of the modules can be applied as drop-in replacements in existing devices based on the families’ modules for 2G, 3G and the various categories of LTE. With Telit’s design-once-use-anywhere philosophy, developers can cut costs and development time by simply designing for the xE910 or xE866 LGA common form factors, giving them the freedom to deploy technologies best suited for the application’s environment.

Integrators and providers looking for lower costs, more security and extended product lifecycles now have more options with Telit’s Verizon-certified LTE and VoLTE modules. Telit’s certified modules may be used by its customers in segments like telematics, home and business security, person and asset tracking, wellness monitoring for the elderly and convalescent, smart home and smart buildings.

The LM940 module boasts a power-efficient platform and is the ideal solution for commercial and enterprise applications in the network appliance and router industry, such as branch office connectivity, LTE failover, digital signage, kiosks, pop-up stores, vehicle routers, construction sites and more. This module includes Linux and Windows driver support.

Texas Instruments (TI) has introduced three new digital-input Class-D audio amplifiers that enable engineers to deliver high-resolution audio in more smart-home and voice-enabled applications. By combining first-of-its-kind integration, real-time protection and new modulation schemes, TI’s new audio devices allow designers to reduce board space and overall bill of material (BOM) cost. These new amplifiers are designed for personal electronics applications with any power level, including smart speakers, sound bars, TVs, notebooks, projectors and Internet-of-Things (IoT) applications.

TAS3251 audio amplifier: TI says the TAS3251 is the first integrated digital-input solution to support the highest output power and performance at 2x 175 W, all in one single package. You can enable up to 96-kHz flexible processing and self-protection features including cycle-by-cycle current limit and DC speaker protection with the TAS3251.

Designers can use TI’s PurePath Console software to easily configure the TAS2770, TAS5825M and TAS3251 Class-D audio amplifiers. Engineers can jump-start their design with the TAS2770 Stereo Audio Subsystem Reference Design. Additional resources and reference designs are available to help engineers with their smart speaker designs.

The TAS2770 Class-D audio amplifier is now available in volume quantities through the TI store and authorized distributors. Additionally, preproduction samples of the TAS5825M are now available through the TI store. The TAS3251EVM evaluation module is available today through the TI store and authorized distributors, and production quantities of the TAS3251 amplifier will be available in 2Q 2018.

CUI’s Power Group today has announced the addition of two models to its PBO family of ultra-compact AC-DC power supplies. Outputting 1 W of continuous power, the open frame PBO-1 and PBO-1-B series are housed in vertical and right-angle SIP packages, respectively. The vertical PBO-1 series measures as small as 35 mm x 11 mm x 18 mm (1.38″ x 0.43″ x 0.71″), while the low profile, right-angle PBO-1-B series measures as small as 35 mm x 18 mm x 11 mm (1.38″ x 0.71″ x 0.43″), making them well-suited for industrial systems, automation equipment, security, telecommunications and smart home devices where limited board real-estate is a factor.These high density power supplies feature wide input voltage ranges from 85 to 305 Vac or 70 VDC to 430 VDC for high voltage DC-DC applications. The PBO-1 and PBO-1-B come available with single output voltages of 5 V, 9 V, 12 V, 15 V, and 24 V DC and offer 3,000 VAC input to output isolation. Both series also offer a wide operating temperature range from -40°C to +85°C at full load as well as over current and continuous short circuit protections with auto recovery.

All models further feature class II construction, carry UL 60950-1 safety approvals, and bear the CE safety mark. The PBO-1 and PBO-1-B series are available immediately with prices starting at $4.74 per unit at 100 pieces through distribution.

Cypress Semiconductor has announced an updated version of its turnkey development platform for the IoT that simplifies the integration of wireless connectivity into smart home applications. The Wireless Internet Connectivity for Embedded Devices (WICED) Studio platform now adds iCloud remote access support for Wi-Fi-based accessories that support Apple HomeKit. Developers can leverage iCloud support in the WICED software development kit (SDK) and Cypress’ CYW43907 Wi-Fi MCU to create hub-independent platforms that connect directly to Siri voice control and the Apple Home app remotely. Developers can access the WICED Studio platform, ecosystem and community at www.cypress.com/wicedcommunity.

Using Cypress’ WICED development platform and ultra-low power CYW20719 Bluetooth/BLE MCU, developers can integrate HomeKit support into products such as smart lighting devices, leverage Siri voice control and connect to the Apple Home app seamlessly. WICED Studio provides a single development environment for multiple wireless technologies, including Cypress’ world-class Wi-Fi, Bluetooth and combo solutions, with an easy-to-use application programming interface in the world’s most integrated and interoperable wireless SDK. The kit includes broadly deployed and rigorously tested Wi-Fi and Bluetooth protocol stacks, and it offers simplified application programming interfaces that free developers from needing to learn about complex wireless technologies. The SDK also supports Cypress’ high-performance 802.11ac Wi-Fi solutions that use high-speed transmissions to enable IoT devices with faster downloads and better range, as well as lower power consumption by quickly exploiting deep sleep modes.

The Cypress CYW43907 SoC integrates dual-band IEEE 802.11b/g/n Wi-Fi with a 320-MHz ARM Cortex-R4 RISC processor and 2 MB of SRAM to run applications and manage IoT protocols. The SoC’s power management unit simplifies power topologies and optimizing energy consumption. The WICED SDK provides code examples, tools and development support for the CYW43907.

WICED Studio IoT Development Platform

The WICED platform supports a broad range of other popular cloud services and eliminates the need for developers to implement the various protocols to connect to them, reducing development time and costs. The WICED Studio SDK enables cloud connectivity in minutes with its robust libraries that uniquely integrate popular cloud services such as iCloud, Amazon Web Services, IBM Bluemix, Alibaba Cloud, and Microsoft Azure, along with services from private cloud partners and China’s Weibo social media platform.

In line with the IoT trend toward dual-mode connectivity, the kit supports Cypress’ Wi-Fi and Bluetooth combination solutions and its low-power Bluetooth and Bluetooth Low Energy (BLE) combination solutions. The SDK features a single installer package for multiple wireless technologies with an Eclipse-based Integrated Development Environment (IDE) that runs on multiple operating systems, including Windows, MacOS and Linux.

Cypress’ WICED Studio connectivity suite is microcontroller (MCU)-agnostic and provides ready support for a variety of third-party MCUs to address the needs of complex IoT applications. The platform also enables cost efficient solutions for simple IoT applications by integrating MCU functionality into the connectivity device. Wi-Fi and Bluetooth protocol stacks can run transparently on a host MCU or in embedded mode, allowing for flexible platform architectures with common firmware.

Arrow Electronics recently agreed to distribute and source components and provide technical design support for Conexant’s AudioSmart 2-Mic Development Kit for Amazon Alexa Voice Service (AVS). Conexant recently announced a collaboration with Amazon on an AVS-approved AudioSmart 2-Mic Development Kit. Featuring the Conexant AudioSmart CX20921 high-performance hands-free Voice Input Processor and “Alexa” wake word technology, the Conexant AudioSmart 2-Mic Development Kit will help developers and manufacturers quickly and easily build Alexa-enabled products that provide users with an ideal voice experience.

The Conexant AVS-approved AudioSmart 2-Mic Development Kit is designed to be easily integrated into any third-party AVS system prototype based on the Raspberry Pi. Its dual-microphone voice processing capability recognizes the “Alexa” wake word and delivers speech requests from anywhere in a room—even in noisy, real-world conditions. It also enables voice barge-in capabilities, allowing users to interrupt their Alexa device when it is playing music or other types of sound.

Qorvo recently launched its latest e-book series, Internet of Things For Dummies, in partnership with John Wiley and Sons. The two-volume series—Internet of Things For Dummies and Internet of Things Applications For Dummies—is available as a free download.

Intended for both technical and nontechnical professionals, the e-books cover the basics of the IoT market, RF challenges, and how it’s being implemented.

Shiyan Hu is an assistant professor in the Department of Electrical and Computer Engineering at Michigan Technological University. We discussed his research in the fields of computer-aided design (CAD), very-large-scale integration (VSLI), smart home monitoring, and biochip design.—Nan Price, Associate Editor

Shiyan Hu

NAN:How long have you been at Michigan Technological University? What courses do you currently teach and what do you enjoy most about instructing?

SHIYAN: I have been with Michigan Tech for six years as an assistant professor. Effective September 2014, I will be an associate professor.

I have recently taught the graduate-level “Advanced Embedded System for Smart Infrastructure,” the graduate-level “Advanced Very-Large-Scale Integration (VLSI) Computer-Aided Design (CAD),” and the undergraduate-level “VLSI Design” courses.
The most exciting part about teaching is the interactions with students. For example, questions from students—although sometimes challenging—can be intriguing and it is fun to observe diversified thoughts. In addition, students taking graduate-level courses need to discuss their course projects with me. During the discussions, I can clearly see how excited they feel about their progress, which makes the teaching very enjoyable.

NAN: What “hot topics” currently interest your students?

SHIYAN: Students are very interested in embedded system designs for smart homes, including FPGA design and embedded programming for the scheduling of various smart home appliances to improve convenience and reduce the cost of electricity bills. I also frequently have meetings with students who are interested in portable or wearable electronics targeting health-care applications.

Photo 1: Shiyan and a team of students he advises developed this sensor-based smart video monitoring system.

Photo 2: A 3-D mouse developed by Shiyan and his team.

NAN:Describe your role as director of Michigan Tech’s VLSI CAD research lab.

SHIYAN: I have been advising a team of PhD and MS students who conduct research in the area of VLSI CAD in the Electrical and Computer Engineering (ECE) department. A main research focus of our lab is VLSI physical design including buffer insertion, layer assignment, routing, gate sizing, and so forth. In addition, we have developed some embedded system prototypes such as sensor-based video monitoring and a 3-D mouse (see Photos 1 and 2).

There is also growing collaboration between our lab and the power system lab on the research of a CAD technique for smart-grid systems. The collaboration has led to an innovative optimization technique for an automatic feeder remote terminal unit that addresses cybersecurity attacks to smart power distribution networks. Further, there is an ongoing joint project on an FPGA-based embedded system for power quality prediction.

Although most of my time as the research lab director is spent on student mentoring and project management, our lab also contributes considerably to education in our department. For example, instructional and lab materials for the undergraduate “VLSI Design” course are produced by our lab.

NAN:Tell us more about your smart home research and the technique you developed to address cybersecurity problems.

SHIYAN: My smart home research emphasizes embedded systems that handle scheduling and cybersecurity issues. Figure 1 shows a typical smart home system, which consists of various components such as household appliances, energy storage, photovoltaic (PV) arrays, and a plug-in hybrid electrical vehicle (PHEV) charger. Smart meters are installed at the customer side and connected to the smart power distribution system.

The smart meter can periodically receive updated pricing information from utility companies. The smart meter also has a scheduling unit that automatically determines the operation of each household appliance (e.g., the starting time and working power level), targeting the minimization of the monetary expense of each residential customer. This technology is called “smart home scheduling.”

In the real-time pricing model, utility pricing is determined by the load while the load is influenced by the pricing, forming a feedback loop. In this process, the pricing information is transmitted from the utility to the smart meters through some communication network, which could be wireless or wired. Cyber attackers can hack some access points in the transmission or just directly hack the smart meters. Those impacted smart meters would receive fake pricing information and generate the undesired scheduling solutions. Cyber attackers can take advantage of this by scheduling their own energy-consuming tasks during the inexpensive hours, which would be expensive without a cyber attack. This is an interesting topic I am working on.

Figure 1: This smart home system architecture includes HVAC and several home appliances.

NAN: Describe your VSLI research.

SHIYAN: Modern ICs and chips are ubiquitous. Their applications include smartphones, modern home appliances, PCs, and laptops, as well as the powerful servers for big data storage and processing. In VLSI and system-on-a-chip (SoC) design, the layout design (a.k.a., physical design) often involves billions of transistors and is therefore enormously complex. Handling such a complex problem requires high-performance software automation tools (i.e., physical design automation tools) to achieve design objectives within a reasonable time frame. VLSI physical design is a key part of my research area.

NAN: Are you involved in any other areas of research?

SHIYAN: I also work on microfluidic biochip design. The traditional clinical diagnosis procedure includes collecting blood from patients and then sending it to laboratories, which require space and are labor-intensive and expensive, yet sometimes inaccurate.

The invention of the lab on a chip (a.k.a., biochip) technology offers some relief. The expensive laboratory procedures can be simply performed within a small chip, which provides much higher sensitivity and detection accuracy in blood sample analysis and disease diagnosis. Some point-of-care versions of these have already become popular in the market.

A major weakness of the prevailing biochip technology is that such a chip often has very limited functionality in terms of the quantities it can measure. The reason is that currently only up to thousands of biochemical reactions can be handled in a single biochip. Since the prevailing biochips are always manually designed, this seems to be the best one can achieve. If a single biochip could simultaneously execute a few biological assays corresponding to related diseases, then the clinical diagnosis would be much less expensive and more convenient to conduct. This is also the case when utilizing biochips for biochemical research and drug discovery.

My aim for this biochip research project is to largely improve the integration complexity of miniaturized components in a biochip to provide many more functionalities. The growing design complexity has mandated a shift from the manual design process toward a CAD process.

Basically, in the microfluidic biochip CAD methodology, those miniaturized components, which correspond to fundamental biochemical operations (e.g., mix and split), are automatically placed and routed using computer algorithms. This methodology targets minimizing the overall completion time of all biochemical operations, limiting the sizes of biochips, and improving the yield in the biochip fabrication. In fact, some results from our work were recently featured on the front cover of IEEE Transactions on Nanobioscience (Volume 13, No. 1, 2014), a premier nanobioscience and engineering journal. In the future, we will consider inserting on-chip optical sensors to provide real-time monitoring of the biological assay execution, finding possible errors during execution, and dynamically reconfiguring the biochip for error recovery.

NAN: You’ve earned several distinctions and awards over the last few years. How do these acknowledgments help your research?

SHIYAN: Those awards and funding certainly help me a lot in pursuing the research of fascinating topics. For example, I am a 2014 recipient of the NSF CAREER award, which is widely regarded as one of the most prestigious honors for up-and-coming researchers in science and engineering.

My five-year NSF CAREER project will focus on carbon nanotube interconnect-based circuit design. In the prevailing 22-nm technology node, wires are made from coppers and such a thin copper wire has a very small cross-section area. This results in large wire resistance and large interconnect delay. In fact, the interconnect delay has become the limiting factor for chip timing. Due to the fundamental physical limits of copper wires, novel on-chip interconnect materials (e.g., carbon nanotubes and graphene nanoribbons) are more desirable due to their many salient features (e.g., superior conductivity and resilience to electromigration).

To judiciously integrate the benefits from both nanotechnology interconnects and copper interconnects, my NSF CAREER project will develop a groundbreaking physical layout codesign methodology for next-generation ICs. It will also develop various physical design automation techniques as well as a variation-aware codesign technique for the new methodology. This project aims to integrate the pioneering nanotechnologies into the practical circuit design and it has the potential to contribute to revolutionizing the prevailing circuit design paradigm.

NAN:Give us some background information. When did you first become interested in computer engineering?

SHIYAN: I started to work on computer engineering when I entered Texas A&M University conducting research with professor Jiang Hu, a leading expert in the field of VLSI physical design. I learned a lot about VLSI CAD from him and I did several interesting research projects including buffer insertion, gate sizing, design for manufacturability, and post silicon tuning. Through his introduction, I also got the chance to collaborate with leading experts from IBM Research on an important project called “slew buffering.”

NAN:Tell us more about your work at IBM Research.

SHIYAN: As VLSI technology scales beyond the 32-nm node, more devices can fit onto a chip, which implies continued growth of design size. The increased wire delay dominance due to finer wire widths makes design closure an increasingly challenging problem.
Buffer insertion, which improves an IC’s timing performance by inserting non-inverting buffers or inverting buffers (a.k.a., inverters), has proven to be indispensable in interconnect optimization. It has been well documented that typically more than 25% of gates are buffers in IBM ASIC designs.

Together with my collaborators at IBM Research, I proposed a new slew buffering-driven dynamic programming technique. The testing with IBM ASIC designs demonstrated that our technique achieves a more than 100× speed increase compared to the classical buffering technique while still saving buffers. Therefore, the slew buffering-driven technique has been implemented and deployed into the IBM physical design flow as a default option.

IBM researchers have witnessed that the slew buffering technique contributes to a great reduction in the turnaround time of the physical synthesis flow. In addition, more extensive deployment of buffering techniques leads to superior design quality. Such an extensive buffer deployment-based interconnect synthesis was not possible prior to this work, due to the inefficiency of the previous buffering techniques.

After the publication of this work, various extensions to the slew buffering-driven technique were developed by other experts in the field. In summer 2010, I was invited by the group again to take a visiting professorship working on physical design, which resulted in a US patent being granted.